Penetrators are typically connectors used to pass signals through an outer wall of an undersea pressure vessel and are designed to be mounted in a manner which maintains the pressure seal between the connector and pressure vessel. Connectors having aluminum connector bodies are often used on the walls of such undersea pressure vessels to mitigate galvanic corrosion. However, such connectors have a limited lifetime and a limited robustness. In one alternative solution, coatings are used, either on the pressure vessel or the connector body, to isolate the pressure vehicle material from connector body material. Such coatings have a limited lifetime and thus a time-limited effectiveness, however. In addition, coatings may create additional problems with the seal between the pressure vehicle and the connector, e.g., the seal may interfere with O-rings or other types of gaskets mounted between the pressure vessel and the connector. In another alternative solution, the pressure vessel may be fabricated from non-aluminum galvanically noble materials. However, such galvanically noble corrosion-resistant metallic materials, e.g., stainless steel, Inconel, Titanium, are both heavier and much more costly than aluminum. The design of efficient subsea unmanned underwater vehicle (one type of undersea pressure vessel) requires that the total weight be minimized as much as possible.
Conventional connectors have a predetermined size which either limits the thickness of the pressure vessel wall or requires a counter-bore on the inner portion of the pressure vessel. A wall thickness that accommodates commercial off the shelf connectors is not adequate for pressure vessels designed for deep sea applications. In addition, the use of a counter-bore can lead to localized stress concentrations in the pressure vessel wall at the counter-bore, possibly leading to metal fatigue and a consequent shortened lifetime for such pressure vessel.
Accordingly, a need exists in the art for an improved system and method for reducing the effect of galvanic corrosion at penetrators (e.g., connectors) passing through the wall of an undersea pressure vessel.